Types

I've been working through Types and Programming Languages by Benjamin C. Pierce. It's filling in a lot of blanks for me.

According to the drafts, ECMAScript 4 will have an ambitious new type system with optional type-annotation. So for example you could write:

//code without types
function sortLines(text) {
    let lines = text.split(/\r\n?|\n/g);
    lines.sort();
    return lines.join("\n") + "\n";
}

// or with
function sortLines(text : String) : String {
    let lines : [String] = text.split(/\r\n?|\n/g);
    lines.sort();
    return lines.join("\n") + "\n";
}

Exactly what effect these annotations will take some explaining. Suffice to say, life is about to get really interesting. I'm sure I'll be writing more about this in a few weeks.